Jason Bay Enters a Hitter's Nightmare

Jason Bay is set to become the new left fielder for the New York Mets. By doing so he leaves the Green Monster behind and heads to the Monster in Queens that is the vast outfield dimensions and high walls of Citi Field. He also leaves behind some fantasy value, which should knock him down a couple rounds on draft day.

Hitting for AVG is not what Jason Bay is known for. He hits home runs and drives in runners on base. With that come a few steals and, for two seasons in a row, over 100 runs scored. However, if you think Bay is going to hit 35-plus home runs once again in 2010, you may be headed for heartache.

Last January I reached out to Greg Rybarczyk of Hit Tracker Online and asked him, “In your expert opinion, how much (percentage wise?) will the new Citi Field affect power numbers (HR’s) for both right and left handed batters?” He responded:

Well, I did a study earlier in the offseason on Adam Dunn, Manny Ramirez and Jason Bay that suggested that these sluggers would hit 39 percent fewer homers than average at Citi Field—but this isn’t really the comparison we’re after. Compared to Shea Stadium, that factor is more like 30 percent for Manny Ramirez, and the others show a similar reduction.

Then considering that only half the games are at home, cut that in half, so I would say a 15 percent reduction in homers for a Mets power hitter. For a lesser power hitter (take Reyes for example), the reduction could be more severe, as their homers tend to clear the fence by less than those of the power hitters.

He was correct in the fact that Citi Field would dramatically affect home run hitters. After the Bay signing was announced today, I followed up with Mr. Rybarczyk and posed the question, “(I was) wondering if that number (39 percent) would still hold now that you have a full season of data on Citi Field. Obviously this is directly related to today’s news that Jason Bay just signed a four-year deal with the Mets.”

To which I received this response:

"I did that study after the 2008 season, and I haven’t come up with any reason to think the results would be significantly different based on what I saw this year. However, Bay’s number was 43 percent fewer (the 39 percent was for all three of those players together)."

Cut 43 percent in half to account for half of Bay’s games coming at home in Citi Field. The charts below show how this would have affected his 2009 home run output as well as how it would affect his 2010 projected home run outputs.

Note : This does not take into account where (home/road) he hit his home runs in 2009. Bay actually hit 21 of his 36 home runs on the road.

That is quite a dramatic drop in home runs as the proposed Citi Field repression keeps his totals all under 30. Are these numbers the final word? No, but if there is one person whose opinion I trust when it comes to the way a ballpark affects home runs, it’s Greg Rybarczyk. The bottom line here is that Bay should most definitely see a regression in home runs and there is a chance he sees a sizeable drop.

The good news is that Bay hits most of his home runs to dead left, which has less drastic dimensions than right and right-center (image below via hittrackeronline.com ).

Note that the scatter plot shows each home run’s “true distance” defined as: If the home run flew uninterrupted all the way back to field level, the actual distance the ball traveled from home plate, in feet. If the ball’s flight was interrupted before returning all the way down to field level (as is usually the case), the estimated distance the ball would have traveled if its flight had continued uninterrupted all the way down to field level.

The fact that Bay pulls the majority of his home runs is certainly a plus as Citi Field’s “killer” dimensions are found from center to right. Still, the difference is obvious and should indeed repress Bay’s power at home.

Moving out of the American League East seems like a positive, as the National League is perceived as the inferior league. I should note, however, that 15 of the top 25 fantasy pitchers according to Mock Draft Central’s ADP data are from the National League. Also, the average FIP* for the National League was 4.18 in 2009 compared to the American League average of 4.39 (Minimum 100 IP).

Bay has not been a good line drive hitter over the past four seasons and both his strikeout rate and whiff rate** have worsened over the last two seasons. Those factors should keep his AVG down once again. Bay hit only .267 last season with a .318 BABIP.

The bottom line is clear: It is unlikely that Jason Bay tops 35 home runs as a member of the Mets and there is a chance that he fails to even reach the 30 home run plateau. He will be hitting in what should be a healthy and improved offense, but we can’t count on a high AVG no matter what.

Given the risk in Bay’s power numbers, a current ADP late in round two/early round three is too high. I’d feel more comfortable if he fell to rounds four or below, but all in all, Bay is a guy I wouldn’t mind missing out on in 2010.

*FIP : Fielding Independent Pitching, a measure of all those things for which a pitcher is specifically responsible. The formula is (HR*13+(BB+HBP-IBB)*3-K*2)/IP, plus a league-specific factor (usually around 3.2) to round out the number to an equivalent ERA number. FIP helps you understand how well a pitcher pitched, regardless of how well his fielders fielded.—The Hardball Times

**Whiff Rate : Simply put, the rate at which a hitter swings and misses.